Fluidic element



United- States Patent Manfred Ruedle Penzberg, Upper Bavaria, Germany 766,927

Oct. 11, 1968 Oct. 13, 1970 lloerbiger Ventilwerke Aktiengesellschaft Vienna, Austria Oct. 13, 1967 Austria inventor Appl. No. Filed Patented Assignee Priority FLUIDlC ELEMENT 4 Claims, 3 Drawing Figs.

US. Cl

Int. Cl

Field of Search 137/815 FlSc 5/00 137/8115 References Cited UNITED STATES PATENTS 3,122,165 2/1964 Horton 137/81.S 3,198,214 8/1965 Lorenz 137/81.5 3,402,728 9/1968 Adams 137/815 3,465,774 9/1969 Kautz et a1 137/815 Primary ExaminerWilliam R. Cline A ttorney-Watson, Cole, Grindle and Watson ABSTRACT: Fluidic element for pneumatic controls, in particular a wall-attachment amplifier comprising a base plate with fluid passages recessed therein and a cover plate for the fluid passages applied to the base plate by gluing or welding.

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FLUIDIC ELEMENT BACKGROUND OF THE INVENTION The invention relates to a fluidic element for pneumatic controls, particularly to a wall-attachment element or amplifier, comprising a base plate wherein passages are recessed, and a cover plate providing airtight covering for the passages.

' Fluidic elements of this type are known to be made of glass or plastic plates, with passages recessed in the base plate generally by etching or milling, whereupon the cover plate is applied either by gluing or by thermal welding of the two plates under pressure. In view of the need for interconnecting relatively large surfaces of the base plate with the cover plate, the thermal welding process requires considerable pressure. Furthermore, air bubbles are liable to be produced which jeopardize the solidity of the connection and are occasionally responsible for leakages in the passages.

SUMMARY OF THE INVENTION It is the object of the invention to improve upon similar fluidic elements and to facilitate their manufacture.

The invention consists in a fluidic element for pneumatic controls, comprising a base plate, fluid passages recessed in the base plate, and a cover plate attached to the base plate and covering the passages so as to provide an airtight seal, the base plate presenting in addition to the passages further recesses which are open in the direction of the cover plate, narrow webs being provided separating the passages from the recesses. The cover plate may be attached to the base plate by thermal welding or by gluing of the two plates under pressure.

This design serves to considerably reduce the pressure required for the production of an airtight joint between the base plate and the cover plate of the fluidic element. Moreover, the production of air bubbles in the surfaces to be interconnected is avoided. Consequently, the fluidic elements according to the invention distinguish themselves by the simplicity and ease of their manufacture and by a high degree of solidity.

Preferably the recesses in the base plate occupy the whole of the remaining surface of the base plate between the fluid passages. Only the webs separating the passages from the recesses and marginal webs surrounding the recesses on the periphery of the base plate remain.

Air vents for the recesses leading from the recesses to the outside of the fluidic element may be provided in the base plate and/or in the cover plate for the purpose of preventing air included in the recesses during the manufacture of the fluidic element from deforming the plates softened by heating, during the cooling stage, since the underpressure produced by cooling is allowed to diminish via the air vents. In the event of a leakage of the passages the air vents also serve for the evacuation of the leakage air into the open, thereby preventing the leakage air from penetrating into other passages where it might jeopardize the proper operation of the fluidic element.

At least part of the webs remaining on the base plate may engage in groove-shaped recesses of the cover plate. This design serves to facilitate the assembly of the two plates and to avoid deformation of the webs when the two plates are pressed together. In addition, the sealing of the passages is thereby improved and penetration of plastic materials into the said passages impeded.

BRIEF DESCRIPTION OF THE DRAWING The accompanying drawing illustrates by way of example, two preferred embodiments of the invention. In the drawing:

FIG. 1 shows a plan view of the base plate of the fluidic element according to the invention with the cover plate removed;

FIG. 2 shows a cross-sectional view of the entire fluidic element along line Il-II of FIG. I; and

FIG. 3 shows a sectional view taken along line III-III of FIG. I of another variant of the fluidic element according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The fluidic element which in the embodiment of the invention illustrated is a so-called wall-attachment amplifier, comprises a base plate I wherein fluid passages 2 are recessed and covered by means of a cover plate 3 applied to the base plate I so as to provide an airtight seal of the fluid passages. As illustrated in FIG. I, the fluid, such as air, for example, admitted through a fluid inlet 4 flows in the direction indicated by the arrows through the fluid passages 2 and emerges therefrom via one of two fluid outlets 5 or 6. The two control inlets provided are designated by reference numbers 7 and 8. The fluid passages 2 are recessed into the base plate I generally made of glass or plastics, by milling or etching, whereupon the cover plate 3 is laid upon it and welded together thermally with the base plate 1 under pressure.

As appears in particular from FIG. 2, in addition to the fluid passages 2 further recesses 9 are provided in the base plate 1, which recesses being open in the direction of the cover plate 3 and of any desired depth. The recesses 9 practically occupy all of the surface of the base plate 1 remaining between the fluid passages 2, narrow webs 10 only being left which surround the recesses 9 and separate them from the fluid passages 2. Thus the contact surfaces between the base plate 1 and the cover plate 3 are considerably reduced, so that the pressure required for welding the two plates together diminishes accordingly. For the venting of the recesses 9 air vents 11 are provided which in the embodiment shown are located in the base plate 1, but might also be accommodated in the cover plate 3.

As shown in FIG. 2, on the side facing the base plate I, the cover plate 3 presents an even surface by means of which it rest upon the webs 10. In the embodiment illustrated in FIG. 3, groove-shaped recesses 12 are provided in the base plate 1, in which the webs l0 engage. Thus not only is the assembly of the two plates 1 and 2 facilitated, but above all, the scaling is improved and deformation of the webs 10 when the plates are pressed together is avoided. Furthermore, penetration of plastic material into the fluid passages during the welding together of plates 1 and 3 is impeded.

The invention is applicable not only to wall-attachment am- 7 plifiers as illustrated by way of example in the drawing, but is to no less advantage also suitable for use in connection with fluid dynamic devices or pure fluid elements of other design comprising a base plate and a cover plate, such as in connection with so-called turbulence amplifiers.

Iclaim:

1. A fluidic element for pneumatic controls, comprising a base plate, fluid passages recessed in the base plate, and a cover plate attached under pressure to the base plate and covering the passages so as to provide an airtight seal, the base plate having in addition to the fluid passages further recesses occupying essentially all of the remaining surface of the base plate which are open in the direction extending towards the cover plate and isolated from a fluid circuit of the element, narrow webs provided to separate the passages from the recesses, only said webs and marginal webs surrounding the recesses on the periphery of the base plate being attached to the cover plate.

2. A fluidic element as claimed in claim 1 wherein openings are provided in the base plate in the area of the recesses thereof and, leading from the recesses to the outside of the element.

3. A fluidic element as claimed in claim 1, wherein openings are provided in the cover plate in the area of the recesses in the base plate and leading from the recesses to the outside of the element.

4. A fluidic element as claimed in claim I, wherein grooveshaped recesses are provided in the cover plate, in which at least some of the webs on the base plate engage. 

